Slovakia’s first larger pumped storage power plant, the Dobšiná power plant has been operated since 1953. Following its reconstruction in 2003, its power has increased to 2 x 12 MW. It has a horizontal layout – at one axis it has in the middle a motor-generator and on the one side a Francis turbine and on the other a high-pressure pump. It is also interesting in that it moves water from the Hnilec catchment to the Slaná catchment area.
Slovenské elektrárne operates 31 hydroelectric plants. Their combined output is 1,652.7 MW, representing approximately 38.4% of the Company’s total installed capacity. Majority of the installations is located on the Váh River cascade, or the longest river in Slovakia. On average, the hydroelectric sources generate 2,070 MW annually (consumption of pumped storage power stations excluded), or some 11% of the electricity produced by Slovenské elektrárne.
Because of their very variable power output and operational flexibility, hydroelectric plants are capable to satisfy the swiftly changing demands in the daily-load diagram, pairing nicely with the base load supply covered by nuclear power plants. Slovenské elektrárne has 736.6 MW installed in river hydropower plants and 916.4 MW in pumped storage power stations.